package network;

import javax.imageio.event.IIOReadProgressListener;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;

    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("启动服务器");
        System.err.println("启动服务器");
        ExecutorService service = Executors.newCachedThreadPool();
        while (true) {
            Socket clientSocket = serverSocket.accept();
            //创建线程,每个线程服务一个客户端
//            Thread t = new Thread(() -> {
//                try {
//                    processConnection(clientSocket);
//                } catch (IOException e) {
//                    throw new RuntimeException(e);
//                }
//            });
//            t.start();

            //使用线程池
            service.submit(() -> {
                try {
                    processConnection(clientSocket);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            });
        }
    }

    private void processConnection(Socket clientSocket) throws IOException {
        //打印客户端信息
        System.out.printf("[%s:%d] 客户端上线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
        //获取到Socket 中持有的流对象
        try (InputStream inputStream = clientSocket.getInputStream();
        OutputStream outputStream = clientSocket.getOutputStream()) {
            // 使用 Scanner 包装一下inputStream,就可以方便读取这里的请求.
            Scanner scanner = new Scanner(inputStream);
            PrintWriter printWriter = new PrintWriter(outputStream);
            while (true) {
                //1.读取请求并解析
                if (!scanner.hasNext()) {
                    //如果scanner无法读取出数据,说明客户端关闭了连接,导致服务器这边读取到了"末尾"
                    break;
                }
                String request = scanner.next();

                //2.根据请求计算响应
                String response = process(request);

                //3.把响应写回给客户端
                //此处可以按照字节数组直接来写,也可以有另外一种写法.
                //outputStream.write(response.getBytes());
                printWriter.println(response);
                printWriter.flush();

                //4.打印日志
                System.out.printf("[%s:%d] req=%s; resp=%s\n",clientSocket.getInetAddress(),clientSocket.getPort(),request,response);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            System.out.printf("[%s:%d] 客户端下线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
            clientSocket.close();
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090);
        server.start();
    }

}
